KRAZY K 2000 TA

iTrader: (5)

so my buddy bought a used 2002 firebird and the heads on it are junk,he is going to stick heads off a 6 liter truck on it and it will make more horsepower?i think he is wrong? what ya think

pwrtrip75

iTrader: (8)

it will lower the compression ratio. Your answer is no.

BlackScreaminMachine

iTrader: (17)

Get the part # but like said I am willing to wager with the static Comp Ratio going down will not make as much power.

SINCE he is yanking the heads, why does he not at least have the 6.0L head refreshed and decked. To get something in the high 10.x to 1 range.

Rhino

iTrader: (6)

Stock the 317's will be 72cc. Check my math, but to get to 10:1 on those heads and MLS gasket with a 5.7 you would need 63cc chambers. It would require a mill between .060 and .070. That's a lot of material. If you didn't run into PTV issues, you'd also need to mill the intake side for it to fit properly.
With an .030 Cometic you would mill .040, which is much more realistic.

Over all you'd be better selling the 317's and buying a new set of heads. If you're just wanting to go back to stock the 317's would easily pay for a set of 241's.

PitchblackC3

iTrader: (3)

317s aren't worth much. I see them sell for $40-$50 all the time. I have 2 sets of them sitting in my shop. The only way you would want 317s is in a boost application, and then you might want the iron heads instead anyway. 243s will flow the same as the 317s, but have smaller chambers. Much better for this app, than the 317s.

Rhino

iTrader: (6)

Wow, I'm surprised to see that. I just sold a set for 3 times that locally. I also see them selling for at least $100 here.

xfactor_pitbulls

iTrader: (16)

A set of basic ported 241 or 853 heads will out perform the stock 317 heads all day long. As they sit unmachined the 241s will make atleast the power of the 317 head. Dont forget as well, you are talking about the difference of a 3.900 bore vs. 4.00 bore head on a 3.900 cylinder. Bad idea all the way around. If anything throw some 5.3 heads on there.

KRAZY K 2000 TA

iTrader: (5)

i tried telling that dumb *** but he is one of those guys you cannot tell anything

BlackScreaminMachine

iTrader: (17)

Then thats the case where you let him fry his motor. IF these heads require a 4.000" (which I forgot to consider) then he is double screwed. Just make sure your not helping him on the install.

Rhino

iTrader: (6)

Point him to this thread... that's 6 votes no, 0 votes yes.

The 317's will run on a 3.9 bore, but he won't be remotely happy with the setup. SCR will be 9.4:1 vs the stock LS1 10:1.

Of course... his money, his prerogative.

pwrtrip75

iTrader: (8)

It wont hurt anything. I've had those heads on a 5.3L. You're just dropping the compression a lot thats all.